What to consider when selecting a PC-based CAD/CAM software system.
It’s best to take a systematic approach to evaluating CAD/CAM software.
A good CAD/CAM system can help a machine shop improve the quality of its work, program jobs faster and handle more complex jobs.
But if you own or manage such a shop, how do you start your search for a new CAD/CAM system? And, how do you weed through all the clutter to find what’s right for you?
A good way to begin is to read advertisements in trade magazines to see what’s available and what the newest features are. You should also ask other shop managers about the CAD/CAM software they use.
The Internet is another excellent tool for finding information. Just enter “CAD/CAM” or “CAM” into any popular search engine, such as Yahoo or Lycos. A word of caution about the Web: “Unofficial” Web sites may contain outdated or incorrect information. For the most current information, it’s usually best to stick with Web sites hosted by the companies whose products you are researching.
Another option is to attend trade shows. They offer the opportunity to compare and contrast a variety of software packages in a few hours.
Trade show demonstrations are generally short and display the most exciting features of the software. Demos tend to be rehearsed, though, and are designed to make the software look powerful and easy to use while avoiding any problem areas. Therefore, it’s important to schedule personalized demos once you have narrowed your choice of software suppliers to a few. Then you can see how each system performs with drawings and tool paths that are similar to the work you perform.
When shopping for CAD/CAM software, try to include every person in your shop who will be affected by the new system in the selection and decision-making process. Doing this will expose you to multiple viewpoints, and the system chosen will likely find greater acceptance among those who use it.
As for selection guidelines, there are six key elements that should be considered when comparing CAD/CAM systems: CAD functionality, CAM functionality, NC code output, general software information, software update policies and technical support. The following questions should be answered about each element.
Does the software price include file translators? If you plan to import geometry from other CAD systems, find out if there is an extra cost for geometry translators. If possible, test the file converters with sample files from the other CAD systems using typical geometry. Look for translators that include these formats: IGES, Parasolid, SAT (ACIS Solids), DWG, DXF, CADL, VDA, STL and ASCII.
What entity types can it create, import and export? The ability to create, import and export complex entities such as solids, NURBS (Non-Uniform Rational B-Spline) curves and surfaces allows you to model geometry more easily, both in 2-D and 3-D.
How easy is it to create a model from a print? If you normally work from drawings, have the software representative create geometry from a print during the demo. If time is short, have the rep model a section of a complex print. Be sure you see both 2-D and 3-D geometry creations.
Giving reps one of your prints the first time you meet will be more a test of their experience than a test of their software’s capability. So it is best to send the print in advance, but have them create the part geometry from scratch during the demo.
Can the system create simple and complex tool paths easily? Some companies’ software packages specialize in complex 3-D tool paths, but their 2-D tool paths may be difficult to use. During the demo, note whether it’s easy or difficult to create both 2-D and 3-D tool paths.
What entity types can the system use for machining? Any type of data represented on the screen should be able to have a tool path applied to it. You should be able to “machine” splines, NURBS curves, multiple surfaces and solid models. Also, the software should allow you to machine different types of data, such as a solid and a surface, with one tool path and create this tool path easily.
Are the tool paths and geometry linked? Linked, or associative, tool paths and geometry allow you to make changes to your model or machining strategy and immediately create an updated tool path without re-entering data.
Can the system automatically calculate feeds and speeds? Tool and material libraries should be available from which the system can generate feed rates and spindle speeds automatically.
Does it have built-in gouge and undercut avoidance capabilities? Ask to see examples of these capabilities for various types of tool paths.
Can you manually override machining defaults and protections? These defaults include feed rates, spindle speeds, gouge avoidance and undercut protection.
Will the software automatically optimize feed rates? Ideally, feed rates should decrease as the tool cuts more material and increase as the tool cuts less material. This helps maintain a constant chip load, which extends tool life and results in more efficient cutting. The software should automate this process.
NC Code Output
How does the system create NC output? Many CAD/CAM systems use translation programs, called post-processors, to customize the NC code output. This gives the user the flexibility to handle many different controls.
Does the software price include post-processors? Find out the cost to provide posts for all your machines, as well as the cost to purchase posts later.
Are post-processors customizable by the user? User-customizable post-processors allow you to make changes yourself or with the help of a tech support person.
Is it easy to switch a program from one machine to another? With some CAD/CAM systems, generated tool paths can be transferred from one control to another as they pass through a post-processor. Other systems require you to reprogram the part from scratch when transferring tool paths.
Is visualization of NC code output available? You should be able to see your final NC code machining a part on the screen so you can verify your tool paths and eliminate problems that might arise during actual machining.
General Software Information
Are the CAD and CAM functions in the same package? For convenience and to make it easier to learn how to use, look for a system that doesn’t require you to switch between software applications to create geometry and tool paths.
Are third-party add-on packages available? Although it is best if one company writes the software, the ability to add utilities from other companies can increase the power and flexibility of your system.
What other software is available from the company? Even if you only do milling, you should see if the software developer offers other machining software, such as packages for lathes or wire EDMs. If you expand your machining capabilities later, you’ll be able to purchase a familiar system.
What operating system does the CAD/CAM software require? It should be compatible with the system running in your shop. If it is a more complex operating system, like UNIX, you may need specific training. If the system will run in Windows 95, Windows 98 or Windows NT, it should be 32-bit code, not the old 16-bit code.
Software Update Policies
How much will software updates cost? Some companies charge a fixed amount for each update. Others have you pay an annual maintenance fee regardless of whether they update the software during the year or not.
Can you upgrade the software? You may only need certain functions at first, such as 2-D machining, but at a later time you may wish to expand your capabilities to include more complex functions. Find out if you can upgrade to more powerful functions whenever you wish without being penalized for starting out with only the functions you need.
What technical support is available? Technical support should be available through the software reseller and the software company. You should be able to expect easy-to-understand answers and a quick response.
Also, find out if a bulletin-board service is available. It allows customers with modems to upload problem reports or download new utilities.
How much will technical support cost? Ask if you have to pay an annual charge for support, if you will be charged by the call, or both. Additionally, ask if the reseller charges for technical support it furnishes above and beyond what the software company provides.
Does the company publish customer newsletters? Newsletters can provide technical tips and information about ongoing development of the software.
Many leading CAD/CAM developers sell their software through dealer networks. This means that you can get your CAD/CAM system from a representative who lives and works in your area. These dealers form an important link between you and the CAD/CAM developer by offering the strength and dependability of a large company on a local scale.
Your CAD/CAM dealer also plays an important role in your use of the software. Dealer reps offer technical support, answer questions and make sure you are productive as quickly as possible.
What should you look for when evaluating a dealer? Choose one that offers the following:
Local support. A good dealer will make sure that your shop’s personnel receive the necessary training and support. This can be done through support contracts that let you call whenever you have a question.
Most dealers also offer training, either on- or off-site. And many schools and colleges offer training classes in specific CAD/CAM systems. Your dealer may be able to put you in touch with these institutions.
Corporate support. It’s critical that the software developer fully support the dealership, providing it with the latest information, backup training and technical support. There are a number of reasons this support is important. If you have a highly specialized question that your dealer wants to double-check, he should have full access to the developer to get your question answered.
Also, although your local dealer should do all he can to support you, sometimes he may be tied up helping other users. Make sure that the CAD/CAM developer offers backup technical support in case your dealer is temporarily unavailable.
One type of CAD/CAM software. Top-notch dealers, just like NC programmers, try to find the best CAD/CAM package and stick with it. A dealer who sells several competing products may be spreading his time and expertise too thin. A dealer that offers “best in class” software is more likely to be an expert about that package.
High skill level. When you schedule a demo, ask the dealer to program tool paths for a part that is similar to the parts you typically produce. The representative should be proficient enough to program your part while explaining the process in a way that is clear and easy to understand. This is a sign that he understands your work and will be able to support you in the future.
A good reputation. When you’re investigating CAD/CAM systems, it’s often a good idea to ask other shops for their recommendations. The same is true for a CAD/CAM dealer.
You may want to ask a dealer you don’t know to provide references, and then call some local users to find out what they think of his support and service.
Vendor familiarity with machining. A good dealer will have a working knowledge of the metalworking industry. He may also be able to give you direction, advice and industry contacts, such as machine tool dealers and suppliers.
Your dealer should also be familiar with different types of machining, such as milling, turning and wire EDMing. This helps assure that if you add machines to your shop, your dealer will be able to help set you up with the correct programming software.
Computer hardware becomes obsolete very quickly, requiring you to buy new equipment on a fairly regular basis. A powerful computer is more expensive initially, but it is a better value in the long run and will enhance the performance of your software.
Your PC makes a vital difference to the productivity of your CAD/CAM system. Before choosing a computer, ask about the minimum and the recommended hardware configurations for the software you are buying and for upcoming releases.
Minimum requirements mean the software will run but, perhaps, not optimally. If you buy hardware to meet minimum requirements, you may have to replace or upgrade it soon after. It may also be painfully slow to use.
A computer that meets the software’s recommended requirements will be more expensive, but the improved performance will be worth the extra cost, especially if you are using the software for programming complex 3-D parts. When considering CAD/CAM software, ask the dealer for the minimum and recommended requirements for:
- Processor type (Pentium, Pentium Pro, Pentium III, etc.).
- Processor speed (300MHz, 500MHz, 1GHz, etc.).
- Amount of random access memory (RAM). The more you have the faster your system will run.
- Type of graphics card. The more video RAM on the graphics card, the faster the display.
- Hard disk size.
- Operating system and version.
- Additional hardware, such as a modem or CD-ROM.
When choosing a computer, the best bet is to buy a reputable, name-brand product that comes with a good warranty. If you buy a mail-order computer, you should be able to get replacement parts quickly from the manufacturer. If you buy from a local company, its service people should be knowledgeable enough to solve hardware and configuration problems.
Some companies offer “bargain” computers assembled from generic components for a low price. However, the hardware may not be as “compatible” as advertised and troubleshooting can waste a great deal of your time. Before buying, make an agreement that you can return the computer if your CAD/CAM system doesn’t run properly on it.
When buying a used computer, be sure to get specific information about it before making a decision. If the computer does not meet the recommended hardware specifications for the CAD/CAM system, find out how much it will cost to upgrade it. It could cost more to buy and upgrade a second-hand PC than to purchase a new one.
A good CAD/CAM system will help you improve the quality, efficiency and competitiveness of your shop. But choosing a system, especially your first one, is not a simple process.
The preceding should provide you insights that many shop personnel don’t gain until after they have bought the wrong system. Learn as much as you can about the available products before you purchase one and you will make the best decision the first time out.
About the Author
Ben Mund is marketing manager at CNC Software Inc., Tolland, Conn.
Related Glossary Terms
Way of displaying real-world objects on a flat surface, showing only height and width. This system uses only the X and Y axes.
Way of displaying real-world objects in a natural way by showing depth, height and width. This system uses the X, Y and Z axes.
- computer numerical control ( CNC)
computer numerical control ( CNC)
Microprocessor-based controller dedicated to a machine tool that permits the creation or modification of parts. Programmed numerical control activates the machine’s servos and spindle drives and controls the various machining operations. See DNC, direct numerical control; NC, numerical control.
- computer-aided design ( CAD)
computer-aided design ( CAD)
Product-design functions performed with the help of computers and special software.
- computer-aided manufacturing ( CAM)
computer-aided manufacturing ( CAM)
Use of computers to control machining and manufacturing processes.
Rate of change of position of the tool as a whole, relative to the workpiece while cutting.
- gang cutting ( milling)
gang cutting ( milling)
Machining with several cutters mounted on a single arbor, generally for simultaneous cutting.
Any manufacturing process in which metal is processed or machined such that the workpiece is given a new shape. Broadly defined, the term includes processes such as design and layout, heat-treating, material handling and inspection.
Machining operation in which metal or other material is removed by applying power to a rotating cutter. In vertical milling, the cutting tool is mounted vertically on the spindle. In horizontal milling, the cutting tool is mounted horizontally, either directly on the spindle or on an arbor. Horizontal milling is further broken down into conventional milling, where the cutter rotates opposite the direction of feed, or “up” into the workpiece; and climb milling, where the cutter rotates in the direction of feed, or “down” into the workpiece. Milling operations include plane or surface milling, endmilling, facemilling, angle milling, form milling and profiling.
- nonuniform rational B-splines ( NURBS)
nonuniform rational B-splines ( NURBS)
Type of curve or surface for which the difference between successive knots (parameter values) need not be expressed in uniform increments of 1. See B-spline.
- numerical control ( NC)
numerical control ( NC)
Any controlled equipment that allows an operator to program its movement by entering a series of coded numbers and symbols. See CNC, computer numerical control; DNC, direct numerical control.
Workpiece is held in a chuck, mounted on a face plate or secured between centers and rotated while a cutting tool, normally a single-point tool, is fed into it along its periphery or across its end or face. Takes the form of straight turning (cutting along the periphery of the workpiece); taper turning (creating a taper); step turning (turning different-size diameters on the same work); chamfering (beveling an edge or shoulder); facing (cutting on an end); turning threads (usually external but can be internal); roughing (high-volume metal removal); and finishing (final light cuts). Performed on lathes, turning centers, chucking machines, automatic screw machines and similar machines.
In numerical-control applications, a cut shorter than the programmed cut resulting after a command change in direction. Also a condition in generated gear teeth when any part of the fillet curve lies inside of a line drawn tangent to the working profile at its point of juncture with the fillet. Undercut may be deliberately introduced to facilitate finishing operations, as in preshaving.
On a rotating tool, the portion of the tool body that joins the lands. Web is thicker at the shank end, relative to the point end, providing maximum torsional strength.